Sound damper for signalling devices



July 23, 1957 M. AMANN r AL souun DAMPER FOR SIGNALLING DEVICES 2 Sheets-Sheet '1 Filed 001:. 20, 1953 I INVENTORS IM. AMANN W- GRUGER R. SCHOLPP ATTORNEY July 23, 1957 M. AMANN El AL 2,800,101

scum: DAMPER FOR SIGNAL-LING DEVICES Filed Oct. 20, 1953 2 Sheets-Sheet 2 Fig. 3

. 2! SectionA-A 3 1 L INVENTORS M. AMANN' w. GRUGER- R. SCHOLPP ATTORNEY United States Patent 6 SOUND. DAMPER i on] SI A LII G navlcas Max Amann, Stuttgart-Bad Cannstatt, and Wolfgang Gruger and Robert Scholpp, Stuttgart-Zulfenhausen, Germany, assignors to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application October 20, 1953, Serial No. 387,136

Claims priority, application Germany October 23, 1952 Claims. (Cl. 116-149) In the manufacture of sound generators for the use in telecommunication systems their volume of sound is so adjusted that the signalling ringing will be noticed also in very noisy rooms. However, in some cases such telecommunication apparatus is set up in rooms which are not noisy so that a damping of the signalling ringing appears to be desirable. This is applicable above all to electric bells in telephone apparatus.

In the conventional types of electric bells the bell domes are shiftably arranged by means of an eccentric attachment, thus being capable of adapting their position to the given unchangeable clapper stroke. However, it' is also possible to use the eccentrical fastening for achieving a modification of the sound volume. In these cases a reduction of the sound intensity will only be obtained by a soft striking of the clapper. In further conventional types of electric bells the same result will be etfected by means of a spring limiting the stroke of the clapper. These arrangements, however, all have the disadvantage that the sound volume is not capable of being readily. regulated. A turning of the bell domes out of range of action of the clapper, of course, will eliminate this drawback, but is not very satisfactory especially in the case of built-in electric bells, because the communication set has to be opened each time an adjustment is to be made.

One object of the present invention is to avoid these drawbacks. This will be achieved in that the sound intensity of the sound generator is changeable by means of an adjustable attenuator acting directly upon the sound generator. According to a further embodiment of the invention said attenuator is designed to be adjustable from the outside of the communication set by the action of screws or levers, which thereby influence the vibrating ability of the sound generator.

The invention will be particularly described with reference to an example of embodiment represented in the accompanying drawing, in which:

Fig. l is a side view of a first embodiment of the invention wherein an attenuator is actuated by means of a slotted head screw or knurled screw;

Fig. 2 is a bottom view of the embodiment shown in Fig. 1;

Fig. 3 is a side view of the embodiment of the invention wherein the attenuator is actuated by means of a lever; and

Fig. 4 is a bottom view of the embodiment shown in Fig. 3.

In Figs. 1 and 2 the sound generator is provided with two bell domes 1, which are sounded by the strokes of the striker clapper 2 in the conventional manner. By the application of a bifurcated spring element 3 to the edges of the bell domes or gongs 1, the vibrating ability of the domes will be influenced. Fig. 1 of the drawing shows the above arrangement in a side view. The spring 3 is mounted to a screw-threaded piece 5 by way of a screw 4, this asembly being capable to be lifted or lowered by turning the knurled screw 6 to control the damping pres- 2,800,101 Patented July 23, 1957 sure on thebe'll d'omes 1. Inordr toassure. that the settingiof the spring] 3' and, at. the. same. time, thatof the. screw thread piece 5 is not changed by thetransmitted vibrations. of the. belljdomes a special: spiral spring. 7. is. provided. The incorporated" how 8 is to prevent. the. spring 3 from being displaced sideways, which would" otherwise easily be the case each time when turning the knurled screw 6. To hold spring 3 in position the upper portion of the threaded piece 5, e. g. may have flat sides that fit into the legs of bow 8. Fig. 2 represents a top view of the arrangement as shown in Fig. 1, and from which the slotted spring 3 may be easily recognized. The base plate 13 is not shown in Fig. 2. Owing to the fact that the attenuator, which is designed as a spring 3, is slotted and that its two members are applied to both of the bell domes, a damping of the sound of both bell domes will be enabled even if the bell domes are arranged in an uneven level.

Figs. 3 and 4 show another way of actuating the attenuator. The function is analogous to the arrangement described in Figs. 1 and 2 above. Fig. 3 shows the side view of the arrangement in a sectional elevation. The spring 3' is prolonged backwards and is angled off downwards. The spring 3' is hinged in a holding device 9 and rests by means of a curve-shaped piece 10 against a lever 12 which is equipped with a roller 11. This lever 12 is likewise pivoted in the holding device 9. Its operating arm projects through the base plate 13. By tilting the lever 12 towards the right-hand side, as indicated by the arrow, the roller 11 will be moved over the curve-shaped piece 10, and thereby the slotted spring 3' will be lifted from the bell domes 1. When restoring the lever 12 into the shown position, a tension spring 14 will pull the slotted spring 3 back so that the flaps of the springs will come to lie on the bell domes, whereby the vibrations of the bell will be damped. Fig. 4 shows the top view of the arrangement and permits recognition of the slotted shape of the attenuator which is designed as a spring 3'.

In contrast to the arrangement of Figs. 3 and 4, the arrangement of Figs. 1 and 2 have the advantage that the damping of the vibrations is adjustable in the diiferent stages by turning the knurled screw 6, whereas by actuating the lever 12 the volume of sound is only capable of being adjusted in two stages.

Since the knurled screw 6 and the lever 12 respec tively are designed to operate from the outside of the communication set, it is also possible in such types of sets which may only be opened by specially authorized persons, e. g. with regard to telephone subsets delivered by the Post Ofiice, that the sound intensity of the sound generator may be changed by anyone. The externally arranged parts of the operating levers may be covered up in a suitable way so that they are protected from any unintended displacements.

What is claimed is:

l. A sound generator comprising a base plate, a dome shaped gong mounted with its spheroidal portion against a first side of said plate, an attenuator device positioned for movement in contact with the peripheral edge of said dome and extending in a direction normal to the axis of said dome, means for mounting said device to the first side of said plate and means extending through said plate to the opposite side thereof for adjustably controlling the pressure of said device on said gong, whereby the vibrations of said gong are damped by the opposing forces produced by said base plate and said attenuator device against said gong.

2. A sound generator according to claim 1, wherein said attenuator comprises a spring blade, and wherein said controlling means comprises mechanical means tending to move said spring blade toward and away from said gong.

3. A sound generator according to claim 2, wherein References Cited in the file of this patent said mechanical means comprises an adjustable screw.

4. A sound generator according to claim 2, wherein UNITED STATES PATENTS said mechanical means comprises a lever mechanism. 431,181 Delany July 1, 1890 5. A sound generator according to claim 1, wherein 5 1,297,982 Acopian Mar. 25,1919 said sound generator comprises tWo gongs arranged side- 2,003,785 Ingraham June 4, 1935 by-side and said attenuator means comprises a flat spring 2,490,522 Kearns Dec. 6, 1949 having two blades in contact with individual of said gongs. 

